1 IQP SYS - 1830 Correlation of Textural qualities in a pound cake to the mechanical behavior An Interactive Qualifying Project Report submitted to the Faculty of WORCESTER POLYTECHNIC INSTITUTE in partial fulfillment of the requirements for the Degree of Bachelor of Science By ______________________ Michael Blaess Advisor ______________________ Professor Satya Shivkumar Date: April 27, 2011
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IQP SYS - 1830
Correlation of Textural qualities in a pound
cake to the mechanical behavior
An Interactive Qualifying Project Report submitted to the Faculty of
WORCESTER POLYTECHNIC INSTITUTE
in partial fulfillment of the requirements for the
Degree of Bachelor of Science
By
______________________
Michael Blaess
Advisor
______________________
Professor Satya Shivkumar
Date: April 27, 2011
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Abstract The texture of a pound cake is determined by the mechanical and physical properties of the
overall product. While the effects of ingredients and baking conditions on various types of cakes have
been studied previously, a mechanical model for the development of properties has not been
established. The purpose of this project was to correlate the textural properties of pound cakes
produced under various conditions to their mechanical behavior. Samples were baked at temperatures
of 175 °C, 200 °C, and 225 °C and aged for 0, 1, 3, and 6 days. The compressive and viscoelastic
properties of these cakes were estimated and correlated to texture. Various changes occurring during
the baking of cake were demonstrated and the time needed to transition from a brittle to plastic foam
was established. The data can be used to assess the effects of baking on texture and highlight the
changes occurring during storage.
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Table of Contents Abstract ......................................................................................................................................................... 3
Table of Figures ............................................................................................................................................. 5
Table of Tables .............................................................................................................................................. 6
Appendix B – Stress - Strain Curves after 0 Days of Baking ........................................................................ 25
Appendix C – Stress - Strain Curves after 1 Day of Baking .......................................................................... 26
Appendix D – Stress - Strain Curves after 3 Days of Baking ........................................................................ 27
Appendix E – Stress - Strain Curves after 6 Days of Baking ........................................................................ 28
Appendix G – Measurement of Temperature in Sample .......................................................................... 29
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Table of Figures Figure 1 - Standard Pound Cake .................................................................................................................... 8 Figure 2 - Examples of Food Foams: (a) Bread, (b) Meringue, (c) Chocolate Bar, (d) Junk Food Crisp, (e) Malteser, (f) Jaffa Cake ................................................................................................................................ 9 Figure 3 - Open Cell Foam Formation ........................................................................................................... 9 Figure 4 - Open Cell under Compression ...................................................................................................... 9 Figure 5 - Brittle Open Cell Foam under Compression ................................................................................. 9 Figure 6 - Elastomeric Foam Stress Strain Curve .......................................................................................... 9 Figure 7 - - Elastic-Plastic Foam Stress Strain Curve ..................................................................................... 9 Figure 8 - - Elastic-Brittle Foam Stress Strain Curve [3] ................................................................................ 9 Figure 9 - Equipment Used during Baking Process ..................................................................................... 12 Figure 10 - Thermal Couple in Commercial Convection Oven .................................................................... 12 Figure 11 - Cake Batter Preparation ........................................................................................................... 13 Figure 12 - Cake Batter undergoing convection cooking in non-stick muffin pan ...................................... 13 Figure 13 - Post Cooked Pound Cake Samples ............................................................................................ 14 Figure 14 - Sample before compression ..................................................................................................... 14 Figure 15 - Sample during compression...................................................................................................... 14 Figure 16 - Sample after compression ........................................................................................................ 14 Figure 17 - Instron Model 4201 Table Top Electromechanical Test System in Washburn Laboratories .... 14 Figure 18 - Mathcad Software for Maillard Reaction Analysis ................................................................... 15 Figure 19 - Stress - Strain Curve (0 Days, 175 °C, Sample 2) ....................................................................... 16 Figure 20 - Stress - Strain Curve (0 Days, 200 °C, Sample 1) ....................................................................... 17 Figure 21 - Sample Baked at 225°C and No Aging Before Compression ..................................................... 17 Figure 22 - Sample Baked at 225°C and No Aging During Compression ..................................................... 17 Figure 23 - S ample Baked at 225°C and No Aging After Compression ...................................................... 17 Figure 24 - Samples Baked at 200 °C and No Aging .................................................................................... 18 Figure 26- Illustration of Heights with Temperature; from left to right (225, 200, 175)°C ........................ 19 Figure 27 - Differences in Crust Thickness with variation of Temperature ; from left to right (225, 200, 175)°C .......................................................................................................................................................... 20 Figure 28 - Differences in Browning Effect ; from left to right (175, 200, 225)°C ....................................... 20 Figure 29 - (0 Days, 175 °C, Sample 1) ........................................................................................................ 25 Figure 30 -(0 Days, 200 °C, Sample 2) ......................................................................................................... 25 Figure 31 - (0 Days, 225 °C, Sample 1) ........................................................................................................ 25 Figure 32 - (0 Days, 225 °C, Sample 2) ........................................................................................................ 25 Figure 33 - (1 Day, 175 °C, Sample 1) .......................................................................................................... 26 Figure 34 - (1 Day, 175 °C, Sample 2) .......................................................................................................... 26 Figure 35 - (1 Day, 200 °C, Sample 1) .......................................................................................................... 26 Figure 36 -(1 Day, 200 °C, Sample 2) ........................................................................................................... 26 Figure 37 - (1 Day, 225 °C, Sample 1) .......................................................................................................... 26 Figure 38 - (1 Day, 225 °C, Sample 2) .......................................................................................................... 26 Figure 39 - (3 Days, 175 °C, Sample 1) ........................................................................................................ 27
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Figure 40 - (3 Days, 175 °C, Sample 2) ........................................................................................................ 27 Figure 41 - (3 Days, 200 °C, Sample 1) ........................................................................................................ 27 Figure 42 -(3 Days, 200 °C, Sample 2) ......................................................................................................... 27 Figure 43 - (3 Days, 225 °C, Sample 1) ........................................................................................................ 27 Figure 44 - (3 Days, 225 °C, Sample 2) ........................................................................................................ 27 Figure 45 - (6 Days, 175 °C, Sample 1) ........................................................................................................ 28 Figure 46 - (6 Days, 175 °C, Sample 2) ........................................................................................................ 28 Figure 47 - (6 Days, 200 °C, Sample 1) ........................................................................................................ 28 Figure 48 -(6 Days, 200 °C, Sample 2) ......................................................................................................... 28 Figure 49 - (6 Days, 225 °C, Sample 1) ........................................................................................................ 28 Figure 50 - (6 Days, 225 °C, Sample 2) ........................................................................................................ 28 Figure 51 - Internal Temperature of Cake Batter during 175 C Baking ...................................................... 29
Table of Tables Table 1 - Cake Batter Ingredients by Weight .............................................................................................. 12 Table 2 - Measure of Strain on aged 225 °C Samples ................................................................................. 17 Table 3 - Measure of Strain on Various Samples ........................................................................................ 17 Table 4 - Measure of Elastic Modulus on Various Samples ........................................................................ 18 Table 5 - Average Heights Before and After Baking .................................................................................... 18 Table 6 - Intensity Values with varied Temperature ................................................................................... 19
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1. Introduction
In recent years, Food Engineering has progressed dramatically as research teams have
conducted studies examining the changes in physical and mechanical behavior with varied ingredients
and processes. Specifically, research in pound cakes has examined the roles of starch, gluten, and
protein of the functionality of the pound cake system and the changes in the mechanical properties. In
order to advance the understanding of pound cakes, the temperature and aging of the sample were
examined the changes in the stress-strain relationship, maillard reaction, and volume expansion.
The pound cake a simple recipe in which all standard ingredients are within a 1:1 ratio with one
another. Pound cake is a cellular solid, a recurring material in nature and industry in which the basic
structural unit is a repeating unit. The standard pound cake recipe utilizes both mechanical and chemical
agents to incorporate air into the batter. The incorporation of air causes the resulting cellular solids to
form a foam. The known behavior of cellular foams can be used to determine the physical and
mechanical properties of the pound cake system under varied temperature and time after baking. For
example, the behavior of the stress-strain relationship for brittle and non-brittle cellular foams is known.
In any study, the adherence to a standard is necessary to produce reliable data and allow the
repeatability of the study. The standards set by the American Association of Cereal Chemists (AACC)
were followed in order to achieve this.
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2. Background Research
In recent years, the study of pound cakes has examined the effect of proportions or modified of
ingredients on the physical and mechanical properties. Previous research on pound cake systems have
focused on the variance the modification of different ingredients
2.1 Pound Cake
A Pound cake made of butter, eggs, sugar, and flour in a 1:1 ratio. The name Pound cake is
derived from the traditional recipe containing roughly one pound of the four ingredients. Other
ingredients are added for mechanical purposes (i.e. baking power) and taste (i.e. vanilla extract, ect.).
Figure 1 - Standard Pound Cake [1]
2.2 Cellular Solids
A cellular solid constitutes “an interconnected network of solid struts or plates which form the
edges and faces of cells” or three-dimensional structural networks with repeating units [2]. Foams, a
subgroup of cellular solids, are unique because gas is introduced mechanically or chemically into the mix
prior to formation. The process to create a foam principally involves (1) mixing cake batter (mechanical
stirring) and (2) adding baking powder (chemical blowing agents) to incorporate air into the mixture
resulting in the creation of a foam. Figure 2 shows examples of the cellular solid structure of foams.
Table 6 - Intensity Values with varied Temperature
Figure 26 - Differences in Crust Thickness with variation of
Temperature ; from left to right (225, 200, 175)°C
Figure 27 - Differences in Browning Effect ; from left to right
(175, 200, 225)°C
5.3.1 Relationship between Brittle Material and Maillard Reaction
A relationship between the maillard reaction and mechanical behavior of the brittle crust is
examined after cross referencing observations made during the compression tests. During the
compression tests, the brittle material created during baking temperatures of 200 °C and 225 °C was
caused by the maillard reaction. This material was different from the foam material inside the core.
However, the samples did not exhibit brittle behavior after aging.
5.3.2 Relationship between Height Expansion and Maillard Reaction
A relationship between the baking temperatures is examined after cross referencing
observations made during the height expansion. The samples subjected to higher baking temperatures
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had lower intensities, thicker crusts, greater height expansions, and better formed shapes. Therefore
there is a relationship between the height or volume expansion and the maillard reaction.
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5. Conclusion
The primary discovery made in this study is the dominant role baking temperature has on the
number of material properties of the pound cake. The temperature is the key controlling factor of the
maillard reaction decreasing the intensity of the color by 23.89 when the temperature was increased
from by 50 °C. The role of aging on pound cakes samples was also important because of the difference in
stress-strain behavior when aging was allowed to occur for samples baked at 200 °C and 225 °C. The
pound cake samples no longer exhibited the Elastic-Brittle Foam behavior after 1 day of aging and
behaved like an Elastic-Plastic Foam. Temperature and aging have an inverse relationship with the
elastic strain and contribute to the brittleness of pound cake. It was observed temperature and the
elastic modulus of pound cake also have a direct relationship. However, the relation between aging and
elastic modulus was unable to be determined. The validity of existing data could determine the
relationships between aging and elastic modulus at specific temperatures with current data. The
internal forces and state of the different cellular foams could cause different behaviors in the elastic
modulus at different baking temperatures.
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References [1] "Pound Cake." Word Press. Available from http://giniann.files.wordpress.com/2006/02/pound%20cake.jpg. Internet; accessed 26 April 2011.
[2] Gibson, Lorna J. and Ashby, Michael E. Cellular solids: Structure and Properties. Cambridge: University of Cambridge, 1997.
[3] (Gibson, 1997, 24-175)
[4] Jaeger, H et al. “The Maillard reaction and its control during food processing. The potential of emerging technologies.” Pathologie Biologie. 58, no 3 (2010).
[5] Raeker, Maide Ozbay and Johnson, Lawrence A. “A Micro Method for Cake Baking (High Ratio, White Layer).” Journal of Cereal Chemistry. 72, no.2: 167-172
[6] Bingham, Andrew; Boucher, Christopher; and Boyce, James. “Textural Variations of Pizza in Commercial Establishments” IQP Report. Worcester Polytechnic Institute, 2011.
Additional References
Wilderjans, Edith et al. “The role of gluten in a pound cake system: A model approach based on gluten-starch blends.” Journal of Food Chemistry. 110, no 4 (2008): 909-915
Wilderjans, Edith et al. “A model approach to starch and protein functionality in a pound cake system.” Journal of Food Chemistry. 120, no 1 (2010): 44-51